Fig. 3119.
It consists of a vertical column or standard, upon the face of which a slideway a for the arm b, on which is a slideway c, along which the head for carrying the saw arbor traverses.
When the saw is to be used, the carriage or work table must be locked in position and adjusted so that the saw will come fair in the groove, provided in the table, but it is not necessary to dog or fasten the work to the table, because the saw itself draws the work over fair against the fence.
When the machine is used for gaining, the work must be dogged fast to the table, so that the work and table may be moved accurately together and the widths apart of the gains kept accurate.
Joshua Oldham’s combination saw for grooving or gaining is shown in [Fig. 3121]. It consists of two outside saws, such as shown at the top of the figure, and having spur teeth between the ordinary cutting teeth. The tops of the spur or cross-cutting teeth are a little higher than the other teeth, so that they sever the fiber before the ordinary teeth attempt to remove it, and thus produce very smooth work. The inside pieces, shown at the bottom of the figure, go between the two outside saws, if necessary, to make up the required width of gain. They are made 1⁄8 inch thick, with an odd one 1⁄16 inch thick, and will thus make gains advancing in widths by sixteenths of an inch.
SCROLL SAWING MACHINES.
The scroll sawing machine derives its name from the fact that it is particularly fitted for sawing scroll or curved work by reason of the saw (which is a ribbon of steel with the teeth cut on one edge) being very narrow.